High pressure drum cover

ABSTRACT

A unitary cover is used with a tubular container having an open end with a cylindrical connecting bead at the open end. The unitary cover comprises a central circular wall. An expansion region surrounds the central circular wall. An annular flange has three concentric cylindrical walls defining an E-shaped wall. An outermost and middle cylindrical walls define a channel receivable on the cylindrical connecting bead. An innermost cylindrical wall defines a hinge and is connected to the expansion region.

FIELD OF THE INVENTION

This invention relates to a drum cover and, more particularly, to acover for a high pressure drum.

BACKGROUND OF THE INVENTION

In one form of conventional shipping and storage container, a drumcomprises a tubular container having an open end with a cylindricalconnecting bead at the open end. The connecting bead may be provided bya metal connecting ring rolled onto the side wall or a plasticconnecting ring molded directly to or otherwise adhered to the sidewall. Alternatively, the side wall may be of molded plastic constructionwith an integral connecting bead.

The conventional drum includes a removable cover for closing the openend of the tubular side wall. A typical cover includes a centralcircular wall with a peripheral connecting flange receivable on theconnecting bead so that the circular wall closes the open end of thecontainer. A locking band secures the cover on the drum. While such acontainer may be used for storage purposes, often the containers must belifted by lifting equipment. Advantageously, the drum should be designedto accommodate parrot beak drum lifting devices. If the cover is not ofsufficient thickness, the drum may not pass a typical parrot beak test.Typically, such a cover includes circular channels or rings formed inthe circular wall providing a corrugated or wave-like appearance.

When used in shipping applications, the containers are often designed tomeet certain requirements. These requirements may comprise drop ratings,pressure ratings or the like. One such rating is a liquid U.N rating forZ1.2/50/S/USA/GBC. In this rating, the 1.2 refers to the specificgravity of the contents of the container. The numeral 50 refers to thekPA rating of the container. With such a rating, a container, such as adrum and cover, must be capable of passing a hydro test in which thecontents of the drum is filled with pressurized water. A conventionaldrum cover when subjected to a hydro test might fail as the pressurecauses expansion of the cover which may lift the peripheral connectingflange away from the connecting bead.

The present invention is directed to solving one or more of the problemsdiscussed above in a novel and simple manner.

SUMMARY OF THE INVENTION

In accordance with the invention, there is provided a cover for use witha tubular container for satisfying high pressure requirements.

Broadly, in accordance with one aspect of the invention, there isdisclosed a unitary cover for use with a tubular container having anopen end with a cylindrical connecting bead at the open end. The unitarycover comprises a central circular wall. A concentric ring regionsurrounds the central circular wall. An annular flange comprises adownwardly opening U-shaped channel receivable on the cylindricalconnecting bead. A cylindrical connecting wall connects an inner edge ofthe annular flange, inwardly of the U-shaped channel, to the connectingring region.

It is a feature of the invention that the annular flange and theconnecting wall have a greater wall thickness than the circular wall andthe concentric ring region.

It is another feature of the invention that the concentric ring regioncomprises first and second concentric rings disposed between theconnecting wall and the central circular wall to define a generallycorrugated structure.

It is another feature of the invention that the concentric ring regionis connected at a central portion of the connecting wall.

It is still another feature of the invention that the connecting wallextends downwardly from the concentric ring region to back up the drumopen end.

There is disclosed in accordance with another aspect of the invention, aunitary cover for use with a tubular container having an open end with acylindrical connecting bead at the open end. The unitary cover comprisesa central circular wall. An expansion region surrounds the centralcircular wall. An annular flange has three concentric cylindrical wallsdefining an E-shaped wall. An outermost and middle cylindrical wallsdefine a channel receivable on the cylindrical connecting bead. Aninnermost cylindrical wall defines a hinge and is connected to theexpansion region.

It is a feature of the invention that the annular flange has a greaterwall thickness than the circular wall and the expansion region.

It is another feature of the invention that the expansion regioncomprises first and second concentric rings disposed between the annularflange and the central circular wall to define a generally corrugatedstructure.

It is still another feature of the invention that the expansion regionis connected at a central portion of the innermost cylindrical wall.

It is still another feature of the invention that the innermostcylindrical wall further comprises a downwardly extending backup wallextending downwardly from the expansion region to back up a drum openend.

It is yet another feature of the invention to provide a pair of bungopenings in the central circular wall.

It is yet another feature of the invention that the annular flange is adiameter to be received on a tubular container having a connecting beadin the range of 14″ to 23″.

It is still another feature of the invention that the cover comprises aunitary wall element of synthetic resin.

Further features and advantages of the invention will be readilyapparent from the specification and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a container including a coveraccording to the invention;

FIG. 2 is a top perspective view of the cover of FIG. 1;

FIG. 3 is a bottom perspective view of the cover of FIG. 1; and

FIG. 4 is a cross sectional view of the cover secured to the drum with alocking band.

DETAILED DESCRIPTION OF THE INVENTION

In the illustrated embodiment of the invention, as disclosed in FIG. 1,a shipping and storage container in the form of a drum 12 includes atubular side wall 14 closed by a bottom wall (not shown) and having anopen end 16 to define an interior space 18. A cylindrical connectingbead 20 is at the open end 16. The open end 16 is selectively closed bya closure in the form of a cover 22 in accordance with the inventionremovably secured to the connecting bead 20 with a locking band 24.

In the illustrated embodiment of the invention, the drum 12 comprises acylindrical, blow-molded plastic drum. The drum has a capacity of 35U.S. gallons and the connecting bead 20 has a diameter of about 18″. Asis apparent, the dimensions of the drum 12 may vary and other typicaldimensions of the connecting bead 20 are about 21-½″ and 23″. Typically,for a container of the type described herein, the diameter is in therange of 14″ to 23″. The present invention is directed particularly tothe cover 22 which can be used with drums of other construction, such asmetal, fiberboard, or composite construction, as will be apparent.

Referring to FIGS. 2 and 3, the cover 22 is illustrated in greaterdetail. The cover 22 may be sized to be used with any one of an 18″,21-½″ or a 23″ drum. As is apparent other sizes could also be used,depending on drum size. The cover 22 comprises a unitary wall element ofmolded synthetic resin, such as high density polyethylene. The cover 22includes a central circular wall 26. The central circular wall 26comprises a circular planar panel 28 of a size corresponding to thecontainer open end 16. A pair of conventional threaded bung openings 30and 32 are provided in the panel 28. The central circular wall 26 issurrounded by an expansion or concentric ring region 34 comprisingpleated or bellow-like concentric rings 36 and 38 stamped or moldedintegrally with the cover 22. The concentric rings 36 and 38 define agenerally corrugated or wavelike structure around the periphery of thecentral circular wall 26.

Referring also to FIG. 4, the circular panel 28 has a flat upper surface42 having a peripheral edge 44. The first concentric ring 36 is radiallyoutwardly of the peripheral edge 44 and is generally an inverted U-shapehaving a shorter side 46 joined to the center wall peripheral edge 44and a longer side 48. The second concentric ring 38 is radiallyoutwardly of the first concentric ring 36 and is generally an invertedU-shape having a longer side 50 and a shorter side 52. The longer side50 is joined to the first concentric ring longer side 48 at a lower peak54.

An annular peripheral flange 60 is radially outwardly of the expansionregion 34. The peripheral flange 60 comprises an upper annular wall 62connected to three downwardly extending concentric cylindrical walls 64,66 and 68. As such, the peripheral flange 60 is “E-shaped” incross-section. The outermost cylindrical wall 64 and the middlecylindrical wall 66 define a downwardly opening U-shaped channel 68 forreceiving the connecting bead 20. A gasket 70 in the channel 68 providesa seal between the cover 22 and the drum 12. The innermost cylindricalwall 68 is connected to a downwardly extending backup wall 72 at a bend74. The second concentric ring shorter side 52 connects to the backupwall 72 at a generally mid-portion thereof, just below the bend 74. Assuch, the innermost cylindrical wall 68 and the backup wall 72 define aconnecting wall connecting the expansion region 34 to the peripheralflange 60.

As described, when the cover 22 is mounted to the drum 14, theconnecting bead 20 is received in the channel 68. The connecting bead 20extends upwardly from a flange 76 extending outwardly from the drumtubular side wall 14. The locking band 24 sandwiches the peripheralflange 60, gasket 70 and connecting bead 20 to retain the cover 22 onthe drum 12 in a conventional manner.

In accordance with the invention, the container 12 including the cover22, comprising a high pressure cover, satisfies requirements of UNrating Z1.2/50/S/USA/GBC. The expansion region 34 allows expansion ofthe cover 22 if it is subjected to a drop test. The resulting impact ofproduct on the cover 22 pushes on the cover rather than breaking.Additionally, with a hydro test, the space 18 is filled with pressurizedwater. The concentric rings 36 and 38 expand to take the resultingforce. Additionally, the cover 22 is adapted to hinge at the peripheralflange innermost cylindrical wall 68 where it meets the annular wall 62,at an area noted H. This moves the hinged point away from the contactsurface between the gasket 70 and the connecting bead 20 allowing thegasket 70 to remain in full contact with the connecting bead 20 underhigh pressure conditions. The connection of the second concentric ring38 to the backup wall 72 must be sufficiently below the hinge point H sothat when expansion of the rings 36 and 38 occurs due to hydrostaticpressure, the circular panel 28 pulls on the backup wall 72 to allow thehinging to function properly.

Additionally, the wall thickness of the expansion region 34 is less thanthat of the peripheral flange 60. This is intended to allow theexpansion region 34 to react to pressure changes as needed.

Thus, in accordance with the invention, there is provided a unitarycover including reduced wall thickness in non-critical areas to reduceweight.

1. A unitary cover for use with a tubular container having an open endwith a cylindrical connecting bead at the open end, the unitary covercomprising: a central circular wall, a concentric ring regionsurrounding the central circular wall, an annular flange comprising adownwardly opening U-shaped channel receivable on the cylindricalconnecting bead and a cylindrical connecting wall connecting an inneredge of the annular flange, inwardly of the U-shaped channel, to theconcentric ring region.
 2. The unitary cover of claim 1 wherein theannular flange and the connecting wall have a greater wall thicknessthen the circular wall and the concentric ring region.
 3. The unitarycover of claim 1 wherein the concentric ring region comprises first andsecond concentric rings disposed between the connecting wall and thecentral circular wall to define a generally corrugated structure.
 4. Theunitary cover of claim 1 wherein the concentric ring region is connectedat a central portion of the connecting wall.
 5. The unitary cover ofclaim 1 wherein the connecting wall extends downwardly from theconcentric ring region to backup the drum open end.
 6. A unitary coverfor use with a tubular container having an open end with a cylindricalconnecting bead at the open end, the unitary cover comprising: a centralcircular wall, an expansion region surrounding the central circularwall, an annular flange having three concentric cylindrical wallsdefining an E-shaped wall, an outermost and middle cylindrical wallsdefining a channel receivable on the cylindrical connecting bead and aninnermost cylindrical wall defining a hinge and being connected to theexpansion region.
 7. The unitary cover of claim 6 wherein the annularflange has a greater wall thickness then the circular wall and theexpansion region.
 8. The unitary cover of claim 6 wherein the expansionregion comprises first and second concentric rings disposed between theannular flange and the central circular wall to define a generallycorrugated structure.
 9. The unitary cover of claim 6 wherein theexpansion region is connected at a central portion of the innermostcylindrical wall.
 10. The unitary cover of claim 6 wherein the innermostcylindrical wall further comprises a downwardly extending backup wallextending downwardly from the expansion region to backup the drum openend.
 11. The unitary cover of claim 6 further comprising a pair of bungopenings in the central circular wall.
 12. The unitary cover of claim 6wherein the annular flange has a diameter to be received on a tubularcontainer having a connecting bead in the range of 14″ to 23″.
 14. Theunitary cover of claim 6 wherein the cover comprises a unitary wallelement of synthetic resin.